GB2325450A

GB2325450A - Packaging of poultry

Info

Publication number: GB2325450A
Application number: GB9710583A
Authority: GB
Inventors: Jason Metcalfe
Original assignee: PADLEY G W HOLDINGS Ltd
Current assignee: PADLEY G W HOLDINGS Ltd
Priority date: 1997-05-23
Filing date: 1997-05-23
Publication date: 1998-11-25
Anticipated expiration: 2017-05-23
Also published as: GB2325450B; GB9710583D0

Abstract

In packaging of an eviscerated bird carcass in a sealed package containing a modified gaseous atmosphere, a jet of the gas is directed into the hollow interior of the carcass 30 by means of a lance 19. The lance is acceleratable towards the interiors of, in particular, cooked chicken carcasses travelling into the packaging film of a horizontal form-fill-seal machine so that each packaged carcass contains the gas as well as being surrounded by the gas within the sealed film. The gas in the package includes by volume 3% oxygen or less.

Description

IMPROVEMENTS IN OR RELATING TO POULTRY This invention concerns improvements in or relating to poultry. In particular, the invention relates to a method and apparatus for producing a whole, cooked, ready to eat chicken that has an extended shelf-life (of 15 days or more).

It is known to pack various perishable foodstuffs by sealing them within eg. envelopes made of flexible, plastics barrier film that entraps a volume of a gas, such as a mixture of nitrogen and carbon dioxide. The gas significantly slows the normal, bacterial decay of the perishable food product. This process is known as "modified atmosphere packaging" (MAP) or "controlled atmosphere packaging" (CAP). The acronym MAP is herein used to describe this process and the gases and apparatuses associated therewith.

MAP packaging of poultry and (other meat products) conventionally takes place in vertical or horizontal form-fill-seal machines, or thermoformed or tray lidded machines that dispense an elongate tube of flexible, plastic packaging film over the end of a feed conveyor on which the poultry products travel.

The tube of packaging film is filled with MAP gas (under a slight pressure) that surrounds each food product entering it, thus displacing the majority of atmospheric air around the product. Sealing of the opposite walls of the tube to one another on either side of the food product results in entrapment of the volume of MAP gas surrounding it.

In order to achieve an extended shelf-life for ready to eat poultry products, it is necessary to reduce the oxygen content within the MAP package to 2-3 %. This is sufficiently low to inhibit the growth of aerobic bacteria, and sufficiently high to inhibit the growth of anaerobic bacteria, for 15 days or more in the case of chicken meat.

The use of MAP techniques has in recent years enabled the mass production of an exceptionally wide range of ready to eat non-frozen food products. However, there remains a need for improvements in MAP technology to permit the mass production of some foodstuffs that hitherto have been impossible to manufacture in an extended shelf-life form.

In particular, there is a need to pack whole, cooked (eg. roasted) poultry and other bird carcasses so as to have extended shelf-lives.

The primary difficulty in packaging such products results from evisceration of the bird carcasses prior to cooking. The evisceration process creates a hollow cavity within the carcass that is open primarily at the vent end of the bird. The neck of the carcass can sometimes include a small vent.

The hollow cavity interferes with the MAP process, since it entraps a volume of ambient air. The volume and direction of supply of MAP gas in the tube of packaging film are insufficient to displace the ambient air from within the hollow cavity in the time available so that the ambient air is sealed within the packaging film on completion of the pack.

Ready to eat chicken products sometimes include surface flora the growth of which is stimulated by 02. These accelerate the decay of the poultry product. Also, after sealing of the pack the ambient air tends to migrate from within the hollow cavity thereby diluting the volume of MAP gas within the package. This reduces the effectiveness of the MAP gas in preserving the carcass.

As a result of such gas migration, it has not previously been possible to mass produce satisfactory, consistent MAP packages for whole, cooked poultry carcases having the desired (maximum 3% 02) atmosphere.

It is known to employ a machine that utilises a two stage process, that does not specifically evacuate ambient air from the cavity, to purge ambient air from the hollow cavity and then surround the bird carcass with MAP gas prior to sealing of a packaging membrane to enclose it.

However, this process requires expensive yet inflexible machinery in which only one pack size can be processed at a time, using a fixed mould.

A pack size change requires a N1 machine reset, which is time consuming.

According to a first aspect of the invention, there is provided a method of packaging an eviscerated bird carcass comprising the steps of: (i) moving the carcass into a region of pressurised, MAP gas thereby surrounding the carcass with MAP gas; (ii) directing a jet of MAP gas into the hollow interior of the moving carcass thereby flushing the said interior with MAP gas; and (iii) sealing the surrounded, flushed carcass within an enclosing barrier.

The step of directing a jet of MAP gas into the interior of the moving carcass advantageously permits mass production of extended shelf-life poultry products.

The step of moving the carcass into a region of pressurised MAP gas advantageously ensures that MAP gas remains in the hollow interior of the carcass after directing of the jet of MAP gas.

It is desirable to generate a clear vent in the carcass before packaging.

This may in accordance with the invention be achieved by pushing material (such as fat), that would otherwise block or limit the vent, inside the cavity after evisceration thereof.

Preferably the step of directing a jet of MAP gas into the interior of the carcass generally occurs contemporaneously with entry of the carcass into the region of MAP gas. This allows the use of a lance or probe sited externally of the enclosing barrier for flushing of the interior of the carcass. The applicants have found that MAP gas thus added to the hollow cavity of the carcass remains therein for a time sufficient for the carcass to move fully into the region of MAP gas which latter then retains MAP gas within the hollow cavity.

The method preferably includes accelerating a jet of MAP gas towards the said hollow interior as the carcass moves into the said envelope.

This ensures that the jet of MAP gas successfully flushes the interior of the moving carcass. It also allows the jet to be initiated at a point clear of the carcass, thereby ensuring that a probe or lance issuing the MAP gas does not collide with the carcass.

Conveniently the envelope is a tube of packaging film dispensed in a horizontal form-fill-seal machine. This feature particularly suits the method for use in the continuous, mass production of extended shelf-life whole chicken carcasses.

Conveniently the jet of MAP gas is dispensed from a moveable nozzle.

This advantageously allows the jet to be accelerated as aforesaid.

In a particularly preferred embodiment, the step of accelerating the jet of MAP gas includes the sub step of accelerating the nozzle towards the hollow interior of the carcass.

More particularly, the accelerating of the nozzle includes the sub-steps of rotating the nozzle from an initial position, spaced from an axis generally coincident with the longitudinal axis of the carcass, to an intermediate position in which the nozzle is coaxial with the said axis; and accelerating the nozzle generally along the said axis towards the hollow interior of the carcass.

This conveniently allows the nozzle to be mounted on a so-called semirotary, linear actuator.

Acceleration of the jet of MAP gas may alternatively be achieved through use of a static nozzle that issues a jet that accelerates during passage of a predetermined period of time.

The methods of the invention may optionally include the step of withdrawing the jet of MAP gas from the carcass before sealing of the carcass within an enclosing barrier.

In the mass production of extended shelf-life carcasses, this step allows rapid re-setting of production apparatus, thereby permitting rapid packaging of successive carcasses.

The step of withdrawing the jet of MAP gas optionally includes withdrawing the nozzle from the vicinity of the carcass. This is advantageous even though the carcass is moving generally away from the nozzle, since it is desirable to re-set the nozzle to an initial position for flushing of the interior of a subsequent carcass.

In particularly preferred embodiments, the step of withdrawing the nozzle includes moving the nozzle away from the carcass along a line generally coincident with the longitudinal axis of the carcass; and rotating the nozzle to a position spaced from the said axis.

This series of movements is also consistent with use of a semi-rotary linear actuator that may be easily secured on a horizontal form-fill-seal machine.

The step of withdrawing the jet of MAP gas also optionally includes interrupting the supply of MAP gas constituting the jet of MAP gas.

This advantageously minimises wastage of MAP gas during withdrawal of the nozzle.

In preferred embodiments the jet of MAP gas includes two mutually perpendicular, generally sector-shaped jets of MAP gas originating from substantially coincident sources.

The use of such a jet shape ensures that the jet is capable of entering and flushing the hollow interior of a bird carcass that, for example, is askew on a conveyor carrying the carcasses towards the region of MAP gas under pressure.

In preferred embodiments, the bird carcass is a cooked, ready to eat chicken, although, the process of the invention may be used for fresh uncooked birds.

The method of the invention advantageously may be carried out at the end of a cooking and production line in eg. a poultry factory.

Conveniently the carcass rests on a tray, eg. an expanded foam tray, or a plastic or other tray, that confers rigidity on a package including the carcass. Alternatively, in accordance with the invention, the carcass may be wrapped in the absence of a tray.

In particularly preferred embodiments, the method is carried out using a horizontal form-fill-seal machine under the control of a microprocessor.

Preferably, the microprocessor is embodied in a programable logic controller (PLC).

Conveniently the rate of packaging is greater than 25 carcasses per minute, and may indeed reach 60 carcasses per minute.

Preferably the MAP gas is a mixture of nitrogen and carbon dioxide in a volumetric ratio of 7:3. This ratio has been found to be particularly suitable for packaging of cooked poultry products, although numerous other inert gas mixtures may alternatively be used.

According to a second aspect of the invention, there is provided a mass produced package comprising a flexible barrier sealingly enclosing an eviscerated bird carcass and a gaseous medium, wherein the gaseous medium includes by volume 3% O2 or less.

In practical embodiments, the bird carcass includes a hollow interior filled with the gaseous medium.

The figure of 3 % O2 or less mentioned herein relates to the condition of the gaseous medium immediately after formation of the package.

Conveniently the balance of the gaseous medium is MAP gas.

The barrier preferably encloses a tray on which the carcass rests. The bird carcass is conveniently a cooked, ready to eat chicken.

The foregoing features have not been available in the prior art. The packages according to the invention may conveniently be manufactured using methods as defined herein.

According to a third aspect of the invention, there is provided an apparatus for packaging an eviscerated bird carcass, comprising: a dispenser of flexible barrier material for enclosing a said carcass; a source of MAP gas under pressure for surrounding a said carcass, enclosed by a said barrier, with MAP gas; a jet of MAP gas moveable from a first position remote from a said carcass to a further position in which the jet enters the hollow interior of a said carcass, the source of the jet being withdrawable from the said carcass; and a seal former for sealing the barrier enclosing a said carcass after withdrawal of the source of the jet of MAP gas.

Such an apparatus is suitable for carrying out the method of the invention, and for manufacturing a package according to the invention.

Conveniently the dispenser of flexible barrier material is a horizontal form-fill-seal machine having a dispenser of a tube of packaging film and a conveyor for conveying one or more said carcasses into said tube, the said source of MAP gas under pressure operating to fill the said tube with MAP gas.

This advantageously permits the apparatus to operate at a high rate.

Preferably the source of said jet of MAP gas is a gas nozzle moveable towards and away from the hollow interior of a said carcass on the conveyor.

In particularly preferred embodiments, the nozzle is movably secured on the form-fill-seal machine.

Preferably the gas nozzle is rotatable between a first orientation in which the MAP outlet of the nozzle is spaced from the longitudinal axis of a said carcass on the conveyor; and a second position in which the MAP gas outlet substantially coincides with the said axis.

The apparatus may also optionally include an actuator for accelerating the gas nozzle in generally the same direction as that of movement of a carcass on the conveyor.

Preferably the source of the jet of MAP gas is secured on an output member of a linear actuator; and the linear actuator is, preferably, a semirotary linear actuator.

The foregoing features advantageously allow use of proprietary mounting and actuation apparatuses in the apparatus of the invention.

The gas nozzle may optionally include a pair of MAP gas outlets arranged side by side, each said gas outlet being elongate in cross section and the axes of elongation of the respective outlets being mutually divergent, whereby the MAP gas jet includes two sector-shaped portions expanding in mutually divergent directions.

Such a nozzle permits production of a MAP gas jet that is likely to enter the hollow interior of a poultry carcass even if the carcass is incorrectly mounted on the conveyor of the form-fill-seal machine.

Preferably the source of the jet of MAP gas is secured on an output member of a linear actuator, in particular a semi-rotary linear actuator.

When the linear actuator is a semi-rotary linear actuator, the output member thereof may optionally include a hollow portion, the nozzle being in fluid communication with the hollow portion, and a supply of MAP gas under pressure being connected to the hollow portion whereby MAP gas flows through the hollow portion to the nozzle.

This is an advantageously neat arrangement that permits the nozzle to follow the full range of movements of the semi-rotary linear actuator.

Conveniently the apparatus is operable under control of a microprocessor, especially a microprocessor embodied in a programmable logic controller (PLC).

Conveniently the source of MAP gas and the source of the jet of MAP gas are respectively operatively connected to a supply of pressurised MAP gas (eg. in a gas cylinder or supplied from a factory main) that is a mixture of nitrogen and carbon dioxide in the ratio of 7:3.

In preferred embodiments, the form-fill-seal machine has a throughput in excess of 25 carcasses per minute. Thus the apparatus of the invention may operate sufficiently rapidly as to permit profitable mass production of extended shelf-life whole carcasses.

There now follows a description of preferred embodiments of the invention, by way of example, with reference being made to the accompanying drawings in which: Figure 1 is a perspective view of a horizontal form-fill-seal machine modified in accordance with the invention; Figure 2 shows part of the Figure 1 arrangement in more detail; Figures 3 to 5 show method steps in accordance with the invention; Figure 6 shows one form of PLC and gas connection suitable for use in apparatus according to the invention; Figure 7 is a perspective view of a package according to the invention; and Figure 8 shows part of the Figure 1 apparatus in more detail.

In the drawings there is shown a horizontal form-fill-seal machine 10 that comprises a horizontal conveyor belt 11 for transporting items to be packed towards a packaging film dispensing and sealing mechanism indicated generally by numeral 12.

Film dispensing and sealing mechanism 12 dispenses and opens an elongate tube of flexible packaging film 13 stored on a roller 14.

Operation of the film dispensing and sealing mechanism 12 is itself known, and results in the open end of the tube of packaging film 13 encircling the conveyor belt 11 so that poultry carcasses or other products conveyed on the conveyor belt 11 pass one by one into the tube of packaging film 13.

The tube of packaging film is filled with MAP gas under a slight over pressure, so that any article entering the tube is surrounded by MAP gas.

The film dispensing and sealing mechanism 12 includes heated sealer bars arranged in opposed pairs for sealing together opposed walls of the tube of packaging film thereby sealingly enclosing a carcass and a bubble of MAP gas.

The sealing and knife cutting action of the machine severs the film so that the enclosed carcass is contained within a discrete pack.

The form-fill-seal machine 10 includes a framework 16 secured thereto, offset to one side of the conveyor belt 11. The framework 16 supports a semi-rotary, linear actuator 17 lying generally horizontally. This is a linear actuator, powered by pneumatic or hydraulic fluid or by electric power, having an output shaft 18 that, depending on control signals input to the actuator 17, may be caused either to rotate or to move parallel to the longitudinal axis of the actuator 17. The actuator 17 is such that the rotation and longitudinal movement of the output shaft can if desired occur simultaneously.

The combination of rotational and longitudinal movement of the output shaft could, alternatively, be achieved through eg. the use of a pair of stepper motors one of which is arranged to cause longitudinal movement of the shaft and the other which is arranged to rotate such a shaft.

The free end of output shaft 18 carries a lance 19 that for the majority of its length extends perpendicular to output shaft 18.

The free end 19a of lance 19 turns through approximately 90" to extend generally parallel to (but offset from) the longitudinal axis of output shaft Lance 19 is hollow. Its free end terminates in a nozzle 19b for generating a jet of MAP gas.

As is shown in more detail in Figure 8, lance 19 in the preferred embodiment comprises two side by side tubes 21, 22. The free (open ended) ends of the tubes 21 and 22 are flattened to oval shaped outlets 21a, 22a the longitudinal axes of which extend in mutually orthogonal directions. Gas flowing along the respective hollow tubes 21, 22 tends to produce sector-shaped jets of gas expanding in mutually orthogonal directions as indicated schematically by dotted and chain lines in Figure 8.

This shape of jet is particularly effective at flushing ambient air from the interiors of poultry carcasses.

The tubes 21, 22 of lance 19 are supplied with MAP gas by virtue of their connection to the output shaft 18 of the actuator 17, which shaft 18 is hollow and is connected at its end remote from lance 19, via supply hoses 23, to a source of MAP gas under pressure.

As is evident from Figures 2 to 5, the lance 19 is moveable in the vicinity of the conveyor belt from a first position, in which the major length of the lance 19 extends perpendicular to conveyor belt 11, to an intermediate position in which the probe is rotated 90" towards the conveyor belt so that the cranked, free end portion 19a thereof extends generally parallel to and overlies the conveyor belt 11.

Such rotational movement of the probe 11 is achieved through rotation of the output shaft 18 of the semi-rotary linear actuator 17.

From the intermediate position the lance 19 may be accelerated parallel to the conveyor belt 11, by means of linear extension of the output shaft of actuator 17.

The lance 19 is in the embodiment shown controlled to rotate in the aforesaid way immediately after passage of a carcass past actuator 17.

Thereafter, the acceleration of lance 19 as aforesaid causes the outlets 21a, 22a to tend to catch up with the vent of the carcass as it moves along on conveyor 11.

During this movement MAP gas is supplied through the hollow tubes 21, 22 to emerge from the nozzles 21a, 22a in the manner depicted in Figure 8, so that a jet of MAP gas enters the hollow interior of the carcass thereby flushing out ambient air and filling the interior with MAP gas.

The lance 19 is positioned such that this operation occurs as each carcass enters the open end of the tube of packaging film 13. At this point, the carcass becomes surrounded by MAP gas. It has been found that judicious adjustment of the MAP gas pressure within the tube of film 13 and feeding of each carcass at the correct speed ensures that the hollow interior of each carcass remains full of MAP gas until sealing of the packaging film 13 to create a pack as shown in Figure 7.

After a carcass has been flushed by the lance 19 the probe rotates through 90" until the majority of its length is perpendicular to conveyor belt 11, and then retracts along a linear path to return to its initial position ready for flushing of the interior of a subsequent carcass.

The supply of MAP gas via the output shaft 18 and lance 19 is desirably switched off during this part of the movement of the lance 19.

Operation of the semi-rotary linear actuator 17 and the supply of MAP gas through nozzles 21a, 22a may be initiated by passage of a carcass on conveyor 11 past an optical sensor or other transducer capable of indicating to a microprocessor 24 controlling the apparatus of the invention that the flushing operation is to be initiated.

The reverse stroke of the lance 19 described hereinabove may be initiated by triggering of a further transducer such as an optical sensor by the carcass as it passes a further position along conveyor belt 11.

Microprocessor 24 may be located eg. in a control console or cabinet 25 that also desirably contains a regulator valve 26 and control valve 27 for MAP gas.

The regulator valve 26 supplies MAP gas continuously to the interior of the tube of packaging film 13; whereas the control valve provides a selectively switched supply via the output shaft 18 and lance 19.

As is shown in Figures 2 to 5, the carcasses 30 to be packaged in accordance with the invention travel along conveyor 11 on lightweight trays 35 formed of a plastic material. Thus each completed pack 36 (Figure 7) comprises a cooked chicken 30 on a said tray 35 sealingly enclosed in an envelope 37 of packaging film that also entraps the MAP gas necessary to maintain the extended shelf-life. Testing of a package such as 36 immediately after its production has revealed the atmosphere within the envelope 37 to contain 3% oxygen or less.

The horizontal form-fill-seal machine 10 is capable of a throughput of up to 60 birds per minute, thereby ensuring that the process may be carried out economically and rapidly.

Thus the invention provides a method, apparatus and package that for the first time allows the consistent and repeatable mass production of ready to eat, whole bird carcasses having extended shelf-lives.

Claims

1. A method of packaging an eviscerated bird carcass comprising the steps of: (i) moving the carcass into a region of pressurised, MAP gas thereby surrounding the carcass with MAP gas; (ii) directing a jet of MAP gas into the hollow interior of the moving carcass thereby flushing the said interior with MAP gas; and (iii) sealing the surrounded, flushed carcass within an enclosing barrier.

2. A method according to Claim 1 wherein the step (ii) of directing a jet of MAP gas generally occurs contemporaneously with entry of the carcass into the region of MAP gas.

3. A method according to Claim 2 wherein the step (ii) includes (iia) accelerating a jet of MAP gas towards the said hollow interior as the carcass moves into the said envelope.

4. A method according to Claim 2 or 3 wherein the envelope is a tube of packaging film dispensed in a horizontal form-fill-seal machine.

5. A method according to any preceding claim wherein the jet of MAP gas is dispensed from the moveable nozzle.

6. A method according to Claim 5 when dependent from Claim 3, wherein the step (iia) of accelerating the jet of MAP gas includes the substep of (iib) accelerating the nozzle towards the hollow interior of the carcass.

7. A method according to Claim 6 wherein the step (iib) of accelerating the nozzle includes the sub-steps of (iic) rotating the nozzle from an initial position, spaced from an axis generally coincident with the longitudinal axis of the carcass, to an intermediate position in which the nozzle is coaxial with the said axis; and (iid) accelerating the nozzle generally along the said axis towards the vent of the carcass.

8. A method according to any preceding claim including the step (iv) of withdrawing the jet of MAP gas from the carcass before sealing thereof within an enclosing barrier.

9. A method according to Claim 8 when dependent from Claim 5 wherein the step (iv) includes (iva) withdrawing the nozzle from the vicinity of the carcass.

10. A method according to Claim 9 wherein the step (iva) of withdrawing the nozzle includes (ivb) moving the nozzle away from the carcass along a line generally coincident with the longitudinal axis of the carcass; and (ivc) rotating the nozzle to a position spaced from the said axis.

11. A method according to Claim 8 or any claim dependent therefrom wherein the step (iv) of withdrawing the jet of MAP gas includes (ivd) interrupting the supply of MAP gas constituting the jet of MAP gas.

12. A method according to any preceding claim wherein the jet of MAP gas includes two mutually perpendicular, generally sector-shaped jets of MAP gas originating from substantially coincident sources.

13. A method according to any preceding claim wherein the carcass is a cooked, ready to eat chicken.

14. A method according to any preceding claim wherein the carcass rests on a tray.

15. A method according to any preceding claim when carried out using a horizontal form-fill-seal machine under the control of a microprocessor.

16. A method according to any preceding claim wherein the rate of packaging is greater than 25 carcasses per minute.

17. A method according to any preceding claim wherein the MAP gas is a mixture of nitrogen and carbon dioxide in the volumetric ratio 7:3.

18. A mass-produced package comprising a flexible barrier sealingly enclosing a eviscerated bird carcass and a gaseous medium, wherein the gaseous medium includes by volume 3% O2 or less.

19. A package according to Claim 17 wherein substantially the balance of the gaseous medium is MAP gas.

20. A package according to Claim 18 or Claim 19 wherein the barrier encloses a tray on which the carcass rests.

21. A package according to any of Claims 18 to 22 wherein the bird carcass is a cooked, ready to eat chicken.

22. An apparatus for packaging an eviscerated bird carcass, comprising: a dispenser of flexible barrier material for enclosing a said carcass; a source of MAP gas under pressure for surrounding a said carcass, enclosed by a said barrier, with MAP gas; a jet of MAP gas moveable from a first position remote from a said carcass to a further position in which the jet enters the hollow interior of a said carcass, the jet being withdrawable from the said carcass; and a seal former for sealing the barrier enclosing a said carcass after withdrawal of the source of the jet of MAP gas.

23. An apparatus according to Claim 22 wherein the dispenser of flexible barrier material is a horizontal form-fill-seal machine having a dispenser of a tube of packaging film and a conveyor for conveying one or more said carcasses into said tube, the said source of MAP gas under pressure operating to fill the said tube with MAP gas.

24. An apparatus according to Claim 22 or Claim 23 wherein the source of said jet of MAP gas is a gas nozzle moveable towards and away from the hollow interior of a said carcass in the conveyor.

25. An apparatus according to Claim 24 wherein the gas nozzle is rotatable between a first orientation in which the outlet of the nozzle is spaced from the longitudinal axis of a said carcass on the conveyor; and a second position in which the MAP gas outlet substantially coincides with the said axis.

26. An apparatus according to Claim 24 or Claim 25 including an actuator for accelerating the gas nozzle in generally the same direction as that of movement of a carcass on the conveyor.

27. An apparatus according to any of Claims 24 to 26 wherein the gas nozzle includes two or more MAP gas outlets arranged side by side, each said gas outlet being elongate in cross section and the axes of elongation of the respective outlets being mutually divergent, whereby the MAP gas jet includes two sector-shaped portions expanding in mutually divergent directions.

28. An apparatus according to any of Claims 22 to 27 wherein the source of the jet of MAP gas is secured on an output member of a linear actuator.

29. An apparatus according to Claim 28 wherein the linear actuator is a semi-rotary linear actuator.

30. An apparatus according to Claim 28 or Claim 29 wherein the output member of the linear actuator includes a hollow portion, the nozzle being in fluid communication with the hollow portion and a supply of MAP gas under pressure being connected to the hollow portion whereby MAP gas flows through the hollow portion to the nozzle.

31. An apparatus according to any of Claims 22 to 30 operable under control of a microprocessor.

32. An apparatus according to any of Claims 22 to 31 wherein the source of MAP gas and the source of the jet of MAP gas are respectively operatively connected to a supply of pressurised MAP gas that is a mixture of nitrogen and carbon dioxide in the ratio 7:3.

33. An apparatus according to Claim 23 or any claim dependent therefrom, wherein the form-fill-seal machine has a throughput in excess of 25 carcasses per minute.

34. A method generally as herein described, with reference to or as illustrated in the accompanying drawings.

35. A package generally as herein described, with reference to or as illustrated in the accompanying drawings.

36. An apparatus generally as herein described, with reference to or as illustrated in the accompanying drawings.

Amendments to the claims have been filed as folows 1. A method of packaging an eviscerated bird carcass comprising the steps of: (i) moving the carcass into a region of pressurised, MAP gas thereby surrounding the carcass with MAP gas; (ii) directing a jet of MAP gas into the hollow interior of the moving carcass thereby flushing the said interior with MAP gas; and (iii) sealing the surrounded, flushed carcass within an enclosing barrier.

6. A method according to Claim 5 when dependent from Claim 3, wherein the step (iia) of accelerating the jet of MAP gas includes the sub step of (iib) accelerating the nozzle towards the hollow interior of the carcass.

18. A mass-produced package produced at a rate of at least 25 such packages per minute comprising a flexible barrier sealingly enclosing an eviscerated bird carcass and a gaseous medium, wherein the gaseous medium includes by volume 3 % O2 or less.